The present invention relates to pesticidal or herbicidal compositions.
The most common domestic insect pests are houseflies, mosquitoes and cockroaches.
The common housefly, Musca domestica, occurs throughout the world in domestic situations. Along with similar species, such as, the lesser housefly, blowflies and flesh flies, it contaminates food and spreads diseases, such as, typhoid and cholera, and also carries the eggs of parasitic worms.
The housefly is also a problem on refuse tips and is becoming a progressively greater nuisance in agriculture, where it breeds in deep litter breeding units for poultry and other animals.
The cockroach is ubiquitous in urban situations in the tropics and sub-tropics and is common in heated buildings in Britain, the rest of Europe and North America where food is prepared. Large cockroach populations are found in sewers and drains and many disease organisms have been isolated from them.
The mosquito is both a severe nuisance pest and vastly important as a vector for blood-borne diseases, such as, malaria, yellow fever, dengue and the like.
Control of those insect pests is becoming more urgent as human populations increase and provide more resources for them to breed.
International Patent Application No. WO94/00980 described the ability of electrostatically charged powders to adhere to an insect cuticle, to a surface of a plant or to a surface of an insect trap. However, insecticidal powders, for example magnesium silicate or silica particles impregnated with an insecticide, do not have the necessary characteristics either to be electrostatically charged or to retain such an electrostatic charge and therefore the particles do not become attached firmly to an insect cuticle, to the surface of a plant, or to a surface of an insect trap.
Herbicidal compositions which are in a particulate form also suffer the disadvantage that the herbicidal particles do not adhere firmly to the plants onto which they are sprayed or dusted.
We have now developed pesticidal or herbicidal compositions which are in particulate form and which have improved adherent properties so that they adhere more firmly to the insect, plant or surface onto which they are sprayed or dusted.